The 7.62×39mm round is a rifle cartridge
of Soviet origin that was designed during World War II. It was first
used in the RPD machine gun. Due to the worldwide proliferation of the
SKS and AK-47
pattern rifles, the cartridge is utilized by both military and
civilians alike. 7.62x39mm ammunition is purportedly tested to function
well in temperatures ranging from −50 °C(−58 °F) to 50 °C(122 °F)
cementing its usefulness in extremely cold polar or hot desert
conditions. Shortly after the war, the world's most recognized military
pattern rifle was designed for this cartridge: the AK-47.
The cartridge remained the Soviet standard until the 1970s, and is
still one of the most common intermediate rifle cartridges used around
the world. It was replaced in Russian service by the 5.45×39mm cartridge
which is used by the current issue AK-74 and variants.